For example, in a conventional sensor chip of such a sensor device, a sensing portion for detecting mechanical quantity is displaced when mechanical quantity such as a pressure, a speed of acceleration or the like is applied to the sensing portion, and the sensing portion detects the mechanical quantity based on the displacement. In particular, an example of the sensing portion includes a diaphragm in a pressure sensor, a beam structural body as a movable portion in an acceleration sensor or the like.
In such a sensor device, stress may be applied to the sensor chip due to the differences of coefficients of thermal expansion of the sensor chip, a substrate, a sealing member that seals the sensor chip and the substrate, or the like. The sensing portion of the sensor chip is susceptible to the stress, thereby a detection error may be caused in the sensor device. Therefore, the stress applied to the sensor chip needs to be reduced as much as possible.
JP-A-8-159897 describes a method for mounting a sensor chip with little stress. According to JP-A-8-159897, in order to reduce stress due to a die-bonding material, a substrate is separated from a sensor chip by disposing a glass pedestal between the substrate and the sensor chip thereby stress due to differences of coefficients of thermal expansion thereof can be reduced. Further, by using silicone resin having low elasticity as a resin for bonding the sensor chip, stress due to a die-bonding material can be reduced.